The pipe tees can be used in a variety of industries, and can be divided into the following categories by different types:

1. By the production method, the pipe tee can be divided into the top system, pressing, forging, casting and so on.

2. According to the manufacturing standards, it can be divided into national standard, electric standard, water standard, American standard, German standard, Japanese standard, and Russian standard.

Dimensions and Standards of straight tees and reducing tees

When we talk about a tee NPS 3, an equal or straight tee is intended. With a tee, NPS 3 x 2 a reducing tee is intended. Although, officially a reducing tee will be indicated by 3 diameters, namely 3 x 3 x 2 (A x B x C). The A & B measure stands for the Nominal Pipe Size of Run-Pipe, C measure stands for Nominal Pipe Size of Outlet.

This designation actually is superfluous but comes from the time that tees were available in 3 different ends of diameters, such as 4 x 3 x 2 (A x B x C). In this implementation, of course, it is necessary, to specify 3 different sizes.

That kind of tees is probably no longer available. Applying an equal tee with a concentric or eccentric reducer is now the usual practice.

A straight or equal butt-welding Tee is available for all common diameters.

A Reducing Tee not, because many diameters are not produced, or can not be produced.

As an example: a reducing tee NPS 6 x 4 is a standard item for most suppliers, but a reducing tee NPS 16 x 2 is probably not available by any supplier.

It would also not economical to use an NPS 16 tee with an NPS 2 outlet; in such situations, a Branch Fitting will be used or a Branch Connection will be made.